I am curious if it is better to drill a ball pin under or pin over for heavier conditions, I have a ball that I drilled with a rico drilling or basically pin in center of grip thinking it would be good on heavier shots. just looking for some input, if you need to know the ball is a Brunswick revolver.

Pin over versus pin under is very vague way to relate ball reaction...

Rico is also subject to controversy since it doesn't take into account a bowler's PAP, ball speed, rev rate, axis tilt, or axis rotation.  It's a good layout for rev dominant players where they need a controlled reaction on wet/dry conditions or house shots.

For the strongest ball reaction possible look into the Double Thumb layout.  For you PAP it would roughly be a 45°x4"x30° dual angle layout.  For the true "double thumb" layout you'll want to use a ball that will have enough pin out to enable the use of an extra hole in the positive thumb quadrant.

Storm's recommendation for heavy oil (strong ball reaction) is a 4"x4"x2" layout.

For me being a higher tilt/ Higher axis rotation player. I need and earlier drill angle to help burn tilt and also a lower Val (pin up) for heavier oil. And higher Val ( pin under) to smooth reaction on the drier stuff. Opposite of everything I ever thought. I always struggled with drier or broken down conditions with balls flying off the spot. Finally when I learned I was high tilt I changed my drillings and thing changed for me quickly. I never had anything drilled pin down(higher Val) until recently.

Layouts merely compliment what the ball is designed to do and throwing pin distances out not knowing particular relevant points is useless. If a bowling ball does NOT slow down properly all else s futile.
And btw the Rico (pin in the palm layout) is not merely for high rev players...I have used it on a multitude of styles with much success.
Do not believe blanketing layouts works for everyone or merely going to a program for an appropriate pin to pap will work. You have to take into consideration how the bowler plays the lanes as well as their comfort zone. A strong layout does NOT simply equate to more hook....

Its really about getting the ball to roll at the appropriate time.  This will depend on bowler style/release, the actual lane conditions heavy short vs heavy long..  what's considered heavy?  With this information, an educated guess about layout can be made...  But design of ball and surface preparation will play a big part too...  So it hard to say what is the right answer.  Unfortunately, "it depends" is often the right answer.

I appreciate all the info, it sounds like the most important things are pin to pap distance, pin to psa distance and pin buffer, so ball set up is crucial. I am guessing the rico drilling isn't really good for heavier oil because the pin to pap is usually about 5 inches.

Please remember that surface dictates 70% of ball reaction with layout prob 10- 15%.

Decent heavy oil bowler here!  Due to years of tournaments being FTL I got decent at it.

I can be very rev dominant and throw 11 mph if I feel like it also, by moving way forward on approach and carrying ball very low. 

Enough about me.

Main idea is I found belly or midlane is the enemy unless one is on a league wet dry ie deep crown with dry to the sides is the only thing that loves low rg and heavy surface.  (My Reaction Roll when this is present...unstoppable).

However on flatter or really wet shots once one bellies it doesn't come back.  Righties don't know that because half way through game 1 a hook spot starts to develop....

However in practice and first game for righties and for about 8 games for a lefty, belly or midlane means no or not enough recovery to strike.

Here are some balls I have used on these flatter shots and really been a heavy contender at times.  I point  say (5 to 8 at the breakpoint or 8 to 11) a touch or straight up the boards at the most.

Battle Zone Bullet(yes a pearl), Track Spell(my all time favorite a particle and higher RG), Brunswick Demolition zone.  Medium higher rg or medium RG.  All one had to do was pick the backend to match to your point(break point)!  Up to 50 feet one of these 3 have worked for me!

Besides my Reaction Roll monster on heavy oil league crowns  I have really enjoyed a Revs Leverage Ebonite Pantera.

Thank you to some of my coaches for helping me find these ideas.

Regards,

Luckylefty
PS hope they help. 
PPS league shots....hard!  FTL every day please!